scholarly journals A Way towards Reliable Predictive Methods for the Prediction of Physicochemical Properties of Chemicals Using the Group Contribution and other Methods

2019 ◽  
Vol 9 (8) ◽  
pp. 1700 ◽  
Author(s):  
Robert J. Meier
Keyword(s):  
Physicochemical Properties ◽  
Real Life ◽  
Correlation Coefficients ◽  
Predictive Modelling ◽  
Heat Of Formation ◽  
Predictive Tool ◽  
Actual Application ◽  
Water Partition Coefficient ◽  
Predictive Methods ◽  
Experimental Scientist

Physicochemical properties of chemicals as referred to in this review include, for example, thermodynamic properties such as heat of formation, boiling point, toxicity of molecules and the fate of molecules whenever undergoing or accelerating (catalytic) a chemical reaction and therewith about chemical equilibrium, that is, the equilibrium in chemical reactions. All such properties have been predicted in literature by a variety of methods. However, for the experimental scientist for whom such predictions are of relevance, the accuracies are often far from sufficient for reliable application We discuss current practices and suggest how one could arrive at better, that is sufficiently accurate and reliable, predictive methods. Some recently published examples have shown this to be possible in practical cases. In summary, this review focuses on methodologies to obtain the required accuracies for the chemical practitioner and process technologist designing chemical processes. Finally, something almost never explicitly mentioned is the fact that whereas for some practical cases very accurate predictions are required, for other cases a qualitatively correct picture with relatively low correlation coefficients can be sufficient as a valuable predictive tool. Requirements for acceptable predictive methods can therefore be significantly different depending on the actual application, which are illustrated using real-life examples, primarily with industrial relevance. Furthermore, for specific properties such as the octanol-water partition coefficient more close collaboration between research groups using different methods would greatly facilitate progress in the field of predictive modelling.

scholarly journals Reliability and validity of a new accelerometer-based device for detecting physical activities and energy expenditure

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5775 ◽  
Author(s):  
Yanxiang Yang ◽  
Moritz Schumann ◽  
Shenglong Le ◽  
Shulin Cheng
Keyword(s):  
Energy Expenditure ◽  
Real Life ◽  
Reliability And Validity ◽  
Correlation Coefficients ◽  
Test Reliability ◽  
Free Living ◽  
Health Maintenance ◽  
Intra Class Correlation ◽  
Global Context ◽  
Different Types

Background Objective assessments of sedentary behavior and physical activity (PA) by using accelerometer-based wearable devices are ever expanding, given their importance in the global context of health maintenance. This study aimed to determine the reliability and validity of a new accelerometer-based analyzer (Fibion) for detecting different PAs and estimating energy expenditure (EE) during a simulated free-living day. Methods The study consisted of two parts: a reliability (n = 18) and a validity (n = 19) test. Reliability was assessed by a 45 min protocol of repeated sitting, standing, and walking (i.e., 3 × 15 min, repeated twice), using both Fibion and ActiGraph. Validity was assessed by a 12 h continuous sequence tasks of different types (sitting, standing, walking, and cycling) and intensities (light [LPA], moderate [MPA], and vigorous [VPA]) of PA. Two Fibion devices were worn on the thigh (FT) and in the pocket (FP), respectively and were compared with criteria measures, such as direct observation (criterion 1) and oxygen consumption by a portable gas analyzer, K4b2 (criterion 2). Results FT (intra-class correlation coefficients (ICCs): 0.687–0.806) provided similar reliability as the Actigraph (ICCs: 0.661–0.806) for EE estimation. However, the measurement error (ME) of FT compared to the actual time records indicated an underestimation of duration by 5.1 ± 1.2%, 3.8 ± 0.3% and 14.9 ± 2.6% during sitting, walking, and standing, respectively. During the validity test, FT but not FP showed a moderate agreement but lager variance with the criteria (1 and 2) in assessing duration of sitting, long sitting, LPA, MPA, and VPA (p > 0.05, ICCs: 0.071–0.537), as well as for EE estimation of standing, LPA, MPA, and VPA (p > 0.05, ICCs: 0.673–0.894). Conclusions FT provided similar reliability to that of the Actigraph. However, low correlations between subsequent measurements of both devices indicated large random MEs, which were somewhat diminished during the simulated 12 h real-life test. Furthermore, FT may accurately determine the types, intensities of PA and EE during prolonged periods with substantial changes in postures, indicating that the location of the accelerometer is essential. Further study with a large cohort is needed to confirm the usability of Fibion, especially for detecting the low-intensity PAs.

Validation of Shiphandling Simulation Models

2011 ◽  
Author(s):  
Tor E. Berg ◽  
Edvard Ringen
Keyword(s):  
Simulation Model ◽  
Numerical Models ◽  
Real Life ◽  
Simulation Models ◽  
Test Scheme ◽  
High Quality ◽  
Simulation Tools ◽  
Benchmark Study ◽  
Actual Application

This paper describes the need for improved methods for validating numerical models used in shiphandling simulators. Such models vary in complexity, from rather simplistic models used for initial shiphandling training at maritime training centers to high-quality models used in the study of advanced marine operations. High-quality simulation models are also used in investigations of maritime accidents such as collisions and groundings. The SIMMAN 2008 conference presented the results of benchmarking studies of simulation tools currently used by research institutes, universities and training centers around the world. Many of these tools employ models based on numerical calculations using methods based on potential or viscous fluid flow, experiments using scale ship models (free running or captive) or semi empirical expressions based on regression analysis of previous model tests. The organizers of SIMMAN 2008 made the hull characteristics of certain ship types available for a comparative study of simulation maneuvering models. The outcome of the benchmark study (using IMO standard maneuvers as case study maneuvers) showed that simulated results varied significantly. In the opinion of the authors, there is an urgent need for new validation studies. The first part of this paper discusses the concepts of simulation model fidelity, verification and validation and the present guidelines issued by ITTC for validation of maneuvering simulation models. The second part looks at the outcomes of the SIMMAN 2008 conference and describes MARINTEK’s contribution to the benchmark study. The use of real-world measurements in model validation is briefly discussed. The need for registration of actual test conditions, as well as the types of tests that should be included in a test scheme, are presented. Finally, the authors discuss validation requirements with respect to the actual application of the selected simulation model as an engineering tool that can be transferred to training simulators used by maritime training centers. It is assumed that simplified simulation models may reduce the quality of simulator based training for ship officers. It is believed that increased quality of simulator model will improve the transfer of training from simulators to real life operations and remove some of the uncertainties related to investigation of maritime accidents.

scholarly journals Heat of Formation (Hf): A Predictive Tool For Anti HIV-5-Phenyl-1-H-Imidazole Derivative.

2017 ◽  
Vol 7 (4) ◽  
pp. 2209-2223
Author(s):  
A. K. R. Khan . ◽  
Richa Mishra . ◽  
Krishna Srivastava .
Keyword(s):  
Heat Of Formation ◽  
Imidazole Derivative ◽  
Predictive Tool ◽  
Anti Hiv

scholarly journals Corruption of the Pearson correlation coefficient by measurement error: estimation, bias, and correction under different error models

2019 ◽  
Author(s):  
Edoardo Saccenti ◽  
Margriet H. W. B. Hendriks ◽  
Age K. Smilde
Keyword(s):  
Pearson Correlation ◽  
Measurement Techniques ◽  
Life Sciences ◽  
Real Life ◽  
Correlation Coefficients ◽  
Gene Expressions ◽  
Science Data ◽  
Real Life Data ◽  
Comprehensive Measurement

ABSTRACTCorrelation coefficients are abundantly used in the life sciences. Their use can be limited to simple exploratory analysis or to construct association networks for visualization but they are also basic ingredients for sophisticated multivariate data analysis methods. It is therefore important to have reliable estimates for correlation coefficients. In modern life sciences, comprehensive measurement techniques are used to measure metabolites, proteins, gene-expressions and other types of data. All these measurement techniques have errors. Whereas in the old days, with simple measurements, the errors were also simple, that is not the case anymore. Errors are heterogeneous, non-constant and not independent. This hampers the quality of the estimated correlation coefficients seriously. We will discuss the different types of errors as present in modern comprehensive life science data and show with theory, simulations and real-life data how these affect the correlation coefficients. We will briefly discuss ways to improve the estimation of such coefficients.

scholarly journals Brain connectivity-based prediction of real-life creativity is mediated by semantic memory structure

2021 ◽  
Author(s):  
Marcela Ovando-Tellez ◽  
Yoed Nissan Kenett ◽  
Mathias Benedek ◽  
Matthieu Bernard ◽  
Joan Belo ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Semantic Memory ◽  
Brain Connectivity ◽  
Real Life ◽  
Semantic Relatedness ◽  
Predictive Modelling ◽  
Judgment Task ◽  
Creative Cognition ◽  
Network Properties ◽  
Brain Functional Connectivity

Creative cognition relies on the ability to form remote associations between concepts, which allows to generate novel ideas or solve new problems. Such an ability is related to the organisation of semantic memory; yet whether real-life creative behaviour relies on semantic memory organisation and its neural substrates remains unclear. Therefore, this study explored associations between brain functional connectivity patterns, network properties of individual semantic memory, and real-life creativity. We acquired multi-echo functional MRI data while participants underwent a semantic relatedness judgment task. These ratings were used to estimate their individual semantic memory networks, whose properties significantly predicted their real-life creativity. Using a connectome-based predictive modelling approach, we identified patterns of task-based functional connectivity that predicted creativity-related semantic memory network properties. Furthermore, these properties mediated the relationship between functional connectivity and real-life creativity. These results provide new insights into how brain connectivity supports the associative mechanisms of creativity.

Applicability Domain for QSAR Models

2016 ◽  
Vol 1 (1) ◽  
pp. 45-63 ◽  
Author(s):  
Domenico Gadaleta ◽  
Giuseppe Felice Mangiatordi ◽  
Marco Catto ◽  
Angelo Carotti ◽  
Orazio Nicolotti
Keyword(s):  
Human Health ◽  
Chemical Space ◽  
Real Life ◽  
Applicability Domain ◽  
Quantitative Structure ◽  
Structure Activity ◽  
Physico Chemical ◽  
Predictive Methods ◽  
Qsar Models ◽  
Quantitative Structure Activity Relationships

Quantitative Structure-Activity Relationships are widely acknowledged predictive methods employed, for years, in organic and medicinal chemistry. More recently, they have assumed a central role also in the context of the explorative toxicology for the protection of environment and human health. However, their real-life application has not been always enthusiastically welcomed, being often retrospectively used and, thus, of limited importance for prospective goals. The need of making more trustable predictions has thus addressed studies on the so-called Applicability Domain, which represents the chemical space from which a model is derived and where a prediction is considered to be reliable. In the present study, the authors survey a number of approaches used to build the Applicability Domain. In particular, they will focus on strategies based on: a) physico-chemical, b) structural and c) response domains. Moreover, some examples integrating different strategies will be also discussed to meet the needs of both model developers and downstream users.

Are PROMs passing the message? A reflection with real-life migraine patients

Cephalalgia ◽  
2021 ◽  
pp. 033310242110345
Author(s):  
Raquel Gil-Gouveia ◽  
António Gouveia Oliveira
Keyword(s):  
Clinical Practice ◽  
Outcome Measures ◽  
Intraclass Correlation ◽  
Real Life ◽  
Correlation Coefficients ◽  
Patient Reported Outcome Measures ◽  
Patient Reported Outcome ◽  
Intraclass Correlation Coefficients ◽  
Patient Reported ◽  
Repeated Applications

Background Several patient-reported outcome measures are available to monitor headache impact, but are those reliable in real-life clinical practice? Methods Two identical patient-reported outcome measures (HALT-90 and MIDAS) were applied simultaneously in each clinical visit to a series of patients treated with monoclonal antibodies for migraine and intra-individual agreement was evaluated using the intraclass correlation coefficients. Results Our sample included 92 patients, 92.4% females, 45 years old on average. Moderate (0.50 to 0.75) and even poor (<0.50) ICC were observed in all but the first item of these patient-reported outcome measures in at least one evaluation. Over time, missing data were more frequent and no learning effect was detected. Discussion We observed intra-personal variation in reliability when answering patient-reported outcome measures, persisting in repeated applications, and a decrease in the motivation to respond, which should alert clinicians for these additional challenges in real-life clinical practice.

Correlation Coefficients of Refined-Single Valued Neutrosophic Sets and Their Applications in Multiple Attribute Decision-Making

2019 ◽  
Vol 23 (3) ◽  
pp. 421-426 ◽  
Author(s):  
Changxing Fan ◽  
Keyword(s):  
Decision Making ◽  
Correlation Coefficient ◽  
Correlation Coefficients ◽  
Multiple Attribute Decision Making ◽  
Neutrosophic Sets ◽  
Actual Application ◽  
Multiple Attribute ◽  
Weighted Correlation ◽  
The Ideal

The paper presents the correlation coefficient of refined-single valued neutrosophic sets (Refined-SVNSs) based on the extension of the correlation of single valued neutrosophic sets (SVNSs), and then a decision making method is proposed by the use of the weighted correlation coefficient of Refined-SVNSs. Through the weighted correlation coefficient between the ideal alternative and each alternative, we can rank all alternatives and the best one of all alternatives can be easily identified as well. Finally, to prove this decision making method proposed in this paper is useful to deal with the actual application, we use an example to illustrate it.

scholarly journals Physicochemical Properties of Chemical Pollutants Available in Food Contact Materials (FCM)

2019 ◽  
Vol 281 ◽  
pp. 06001
Author(s):  
Joanna Farhat ◽  
Joseph Saab ◽  
Juliette Stephan ◽  
Antonio Kashanna ◽  
Christelle Goutaudier ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Physicochemical Properties ◽  
Human Health Risk ◽  
Aqueous Solubility ◽  
Potential Effect ◽  
Contact Materials ◽  
Chemical Pollutants ◽  
Water Partition Coefficient ◽  
Recycling Systems ◽  
Recycled Material

Health and welfare of population are priority reasons to study the toxic effects of chemical pollutants. These effects can directly produce deterioration of health or can cause less healthful environment toxicity and restricting food production. Thereby, preventing such a consequence is important for human health risk assessment. In recent times, the use of recycled materials for packaging has undeniably been intensified. Nevertheless, recycling systems could not effectively eliminate the potential effect of chemical pollutants (alkyl phenol, phthalates, aldehydes, etc.) existent in such packages. The migration process and/or the ability of these pollutants to be absorbed into the recycled material, subsequently released by the packaging material, and then trapped by the matrices they contain, has become a potential source of exposure to consumers. This process is controlled by the nature of the packaging, time, temperature, and the physicochemical properties of the contaminant. The literature suffers from a lack of data related to the physicochemical (aqueous solubility, vapor pressure, Henry’s constant, etc...) of these contaminants. In this work, we are going to describe the experimental devices used for aqueous solubility, vapor pressure and octanol/water partition coefficient determination.

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